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Altera_Forum
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13 years ago

PLL critical warning - 400MHz

Dear All, I'm using this device - Cyclone IV - EP4CE22F17C6N I created a PLL with 4 different clock outputs. (using Megafunction) input f = 400MHz output 1 = 100MHz with 90° shift ...
Altera_Forum's avatar
Altera_Forum
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13 years ago

As far as I understand, 2.5V IO standard doesn't support 400 MHz by specification. You would want to refer e.g. to a LVDS input. The PLL Megawizard doesn't take account for IO constraints.